Before the Borg attack, the El-Aurians had traveled widely throughout the galaxy. Their general humanoid appearance and listening ability allowed them to blend in on many worlds, including Earth, where they visited in the 19th century (and perhaps earlier). (TNG: "Time's Arrow")

The El-Aurian lifespan is undetermined, but known to be quite long, with some living to be over 1000 years old. Aside from their long-lived nature, and their perceptive abilities, El-Aurians appear indistinguishable from humans, and frequently intermarry with other species.